Spinning heat sink could lead to faster computers

A redesigned heat exchanger could speed up your home computer, while reducing fan noise and energy use.

Air-cooled heat exchangers haven't changed much in 40 years,
says Jeff Koplow, a researcher at Sandia National Laboratories. A disk absorbs heat from a computer's processor and transfers it to a row of attached metal fins. A fan stirs up the air around the heat sink. But only about five
per cent of that energy provides a cooling effect. Why? A pesky layer of stagnant air clings to the fins, insulating them like a blanket. Spinning the fan faster helps, but it also makes computers intolerably noisy.

These limitations impact processing speed. Chips can run
faster, but the fans can't cool them fast enough to prevent overheating.

(Image: Jeff Koplow)

In this new design, dubbed the "Sandia Cooler," the fan is the heat sink. Bands of metal blades rotate above the heat source atop a thin cushion of air. Centrifugal forces roil that air to facilitate heat transfer. They also compress the layer of stagnant air against the blades, reducing that insulating effect. Cool outside air pushes away dust as it flows through the
center of the spiral and out the sides.

Koplow, who designed the cooler, is working with others to mass-produce
these quiet fans cost-effectively. If they become widely adopted, he estimates
total US electricity consumption could drop by about seven per cent.

"If they become widely adopted, he estimates total US electricity consumption could drop by about seven per cent." You can't be serious.

CPU fans, even really oversized ones for the hard-core overclockers use only 2 or 3 watts, which wouldn't even be 1% of the power the computer uses. And it's not like computers are the only thing we have on the grid.

This is just silly. That figure isn't the only problem, it is just the most obvious.

rwde
on July 12, 2011 1:20 PM

Cool!

Smor
on July 12, 2011 1:46 PM

@Scott. If you read the article again you will notice they are talking about savings in power used by the processor, not the fan.

Good point. The minute anyone comes up with a new energy-saving device, we all use it more. We all work this way with lots of things--anti-lock brakes, for example: turns out most of those who have them wind up driving with just enough extra speed to offset the risk reduction by the better brakes.

Miasere
on July 12, 2011 3:39 PM

Scott, I think the idea here is that it reduces the power consumption of the CPUs rather than the fans, but I would like to see the source for that statistic - it appears very large

Ken
on July 12, 2011 4:04 PM

They physics of this are very questionable at best, why would air blowing past the metal that this is made of be any more efficient than the air blowing past the metal of a stationary heat sink? The laws of thermodynamics apply equally to both. Also sounds like there would be huge issues with actually getting the heat to efficiently transfer through the bearings and into the rotating mass to begin with. This looks like something that will end up in a sharper image catalog and then be gone from memory a few months later. Dust buildup would be a killer on this design as well with the relatively small air inlet, clogging would occur very fast.

The big savings is not in CPU coolers but in air conditioning systems, guys.

Paul Eccles
on July 12, 2011 7:57 PM

Looks like an astonishing breakthrough - this could have massive implications for refrigeration and air-conditioning, making it WAY more efficient. Read the paper, it explains the theory. Hope it works out!

Anentropic
on July 12, 2011 10:32 PM

There's nothing in the text of the article to suggest a reduction in power consumption by the cpu will result.

It says chips can't run faster because the fans can't cool them - that's because the cpu generates more heat and is consuming more power when it runs faster. So more efficient fans would facilitate chips which used more power, offsetting some, or all (we can't judge), of the gain in power efficiency from the fan itself.

Scott is right, the claim in the last sentence about reducing US energy consumption by 7% is not supported by the article. Maybe in the paper they detail other applications like air con and refrigeration to arrive at this figure.

In fact, reading the paper, they mention a figure of "~5%" reduction in US energy consumption... the "seven per cent" of the NS article isn't mentioned anywhere and seems to have been invented?

Brilliant piece of engineering though.

Alex
on July 12, 2011 11:06 PM

I liked the part where the author of the article made up numbers.

Todd
on July 12, 2011 11:10 PM

Well it seems really good and all. But I have one problem. How do you spin the heat sink, and conduct away the heat into it at the same time?

In order to conduct heat through conduction, from solid to solid, you have to have a physical connection. If the heat sink spins, you have to have some "thing" that will allow enough conduction into the heat sink. Like a thermal paste, which by the way, they already use for stationary old fashioned heat sinks. How is this accomplished?

Alex
on July 12, 2011 11:32 PM

@Todd
Did you look at the picture provided in the article?
There is a
Stationary Baseplate,
then there is a
0.001inch air gap
then there is the
Rotating cooling fin/impeller structure

Todd
on July 13, 2011 2:10 AM

lol .001" air gap? base from your previous comment, i'm gonna assume you are being sarcastic. =[ this .001" air gap is laughable at best.

KL
on July 13, 2011 2:52 AM

@Todd. Wow you must not have much experience with machining or other common high precision fields. 0.001" is typically referred to as 1 thou, and its about 1/3rd the thickness of a normal sheet of printer paper. 1 thou is not really a challenging accuracy to hold and even with hobby equipment is easy to achieve. Now when you get in to the "tenths" 0.0001" it becomes a bit more tricky.

If you read the paper attached to the article, they basically explained everything. In great detail. The air bearing (the 0.001" air gap) is pressurized and holds the impeller from coming in contact with the plate (its just like an other air bearing you commonly run in to, say in your hard-drive). The air bearing also acts as the thermal interface, it carries heat of the stationary base plate in to the impeller which "slices" in to the air bearing layer. From there the heat of the latent gas is transferred in to the fins of the heat exchanger and the somewhat cooled gas is expelled away from the heat source.

The only thing I noticed is that the paper was published in January of 2010... So uh, where can I buy one of these coolers?... ... ...

Todd
on July 13, 2011 3:04 AM

All I'm saying is, I'll believe it when I see one. I don't think you could make one, and if you do it'll cost a boat load of money.

Michael Dowling
on July 13, 2011 3:14 AM

Okay,if there is an air gap,even a small one,that doesn't seem like a way to efficiently transfer heat from the chip to the heat sink.Wouldn't liquid cooling work as well if not better,and have no moving parts to boot? For extra cooling,however,liquid coolant could be pumped over the chip.Just sayin..

Patrick Miller
on July 13, 2011 12:51 PM

Moving parts is not the solution. A balanced peltier effect built in to the processor casing that is designed to approach ambient temperature with due consideration of relative humidity and the ability to vary the speed of the processor on demand is the only way to go forward without moving parts or skipping best way to chill - liquid cooling, yeah yeah no 'green' power savings PR there. Condensation can be avoided in a built in peltier system several ways, not dipping below ambient temperature, wicking the sealed cpu... Oh whatever somebody is working on it....

Patrick Miller
on July 13, 2011 1:02 PM

OH...and that 0.001" air gap is only going to work in a clean room so pffft..

Theraot
on July 13, 2011 3:53 PM

And the dust then ends up in your RAM memory end eventually causing it to fail.

Kevin
on July 13, 2011 4:52 PM

Scott,

It's not a reduction in the power that the fan needs to operate, it's the power of the chip. Chips can be made thinner and faster, requiring less power to operate, but as a general rule, the thinner a chip gets, the hotter it can run, meaning the cooling solution has to keep up. We have fans now that can keep up, but they get vacuum-cleaner loud at full speed. This attempts to solve that problem.

Again, it's not the power consumed by the fan(s), but rather the lower power used by the CPU. That's where the power savings is.

mtcoder
on July 13, 2011 6:13 PM

Also most to all electrical components have a sweet spot between performance and power consumption. A standard chip is typically no where at it's peak ratio. Look at overclocking the chip is able to handle more work, with about same consumption of energy but generates heat to the point of not being cooled by conventional methods. Thus the fine line you walk when you overclock. If you could keep heat down and increase overall performance of the cpu into new levels. IE having a 10 ghz processor that stayed cool, you would need less ram, and less bus transfers the cpu could process your information faster. We have sorta went to the direction that the cpu is "capped" out, and put more ram into systems that run super fast, but drain more power.
Computers are a huge piece of the electrical drain. Think about an office with 100 computers in it, sucking down 100watts an hour. 10,000watts an hour. Is a pretty good chunk of energy. And that is low end machines. Seen some places with 500watt power supplies running non-stop at full draw.

piotr1600
on July 13, 2011 7:19 PM

I'm skeptical, to say the least.
If you strip away the nice graphic and consider it, it is a flat plate heat sink with air blown across it.
It has MUCH less surface area than existing heatsink designs. So the air volume requirements are going to be much larger. SO that fan is going to have to move *more* air to achieve the same amunt of cooling. Which means more fan load, which means more fan power...So unless the fan is just magically a *lot* more efficient, I'm not seeing a huge improvement.

And, the center - where the IC - aka "Heat Source" usually resides? With this design it probably sees the least cooling air velocity in the system - and there is the rotating mechanism of the fan located there too - which *also* generates heat...

I've been wrong before, but I truly doubt this design is all it is being hyped up to be...

Grumpy Old Bob
on July 13, 2011 9:21 PM

Please correct me if I'm wrong, but surely the diagram shows the wrong direction of rotation if the airflow direction is from the centre outwards as stated in the text.......

Mr.D
on July 14, 2011 12:49 AM

I think the grey color isnt showing spin direction, it's showing air flow direction (so it should spin in the opp).

Closed loop pulsating heatpipes have came a long way in the past 10 years. Your still stuck with the heat, but moving it away from the processor for disposal makes life a lot easier.

Moving the heat away for disposal is the biggest pain.

-netninja
on July 14, 2011 1:15 AM

Lower power & Quieter are two very significant benefits.
Good ground work for future design improvements.
Some practical duct-work design seems necessary to prevent heated exhaust from mixing with the intake.
Can't wait to see what v2 performance looks like!
-Netninja

Oh, and way too many people are apparently too lazy to read. What a pity the world may be in their hands someday.

Spinning blades of aluminium
on July 28, 2011 11:54 PM

Yes, I always wanted spinning blades of aluminium in my computer.
I also wanted them to be very sharp. I hope they also put that in mass production.